Circuit breaker



J. G. JACKSON CIRCUIT BREAKER Oct. 11, 1938.

Filed May 2, 1936 3 Sheets-Sheet l INVENTOR Jb/zrz 6.5126160 BY A TTORNEY Oct. 11, 1938. J. G. JACKSON CIRCUIT BREAKER Filed May 2, 1956 5 She'ets-Sheet 2 INVENTOR.

'J'Oll 7'az'iaa z A TTORNEY.

Oct. 11, 1938. JACKSON 7 2,132,627

CIRCUIT BREAKER 5 Sheets-Sheet 5 Filed May 2., 1936 JP I 1 :2

L E] 48 I "1 1 l l F I V I I 48 Fl/I I INVENTOR. J 0? 6f \Yhc'ISa Z A TTQRNE Y.

Patented Oct. 11, 1938 UNITED STATES CIRCUIT BREAKER John G. Jackson, Detroit, Mich, assignor to Square D Company, Detroit, Mich, a corporation of -Michigan Application May 2, 1936, Serial No. 77,519

30 Claim.

This invention relates to devices for making and breaking electrical circuits and more particularly to circuit breakers automatically operable in response to current overload.

5 One object of the invention is to provide an improved form of arc chamber for an electric circuit breaker of either single or multi-circuit form.

Another object of the invention is to provide an electric circuit breaker-with an improved are barrier having a restricted slot closely receiving and guiding a movable switching member.

Another object of the invention is to provide an improved contact assembly plate in a multicircuit circuit breaker.

Another object of the invention is to provide an improved sealing means for a circuit breaker minimizing blowing out of arc gases and improve the dielectric characteristics.

30 Another object of the invention is to provide an improved form of magnetic yoke for a multicircuit circuit breaker.

Other objects and features of the invention will be readily apparent to those skilled in the :5 art from the following specification and appended drawings illustrating certain preferred embodiments of the invention in which:

Figure 1 is a front view of a multi-circuit circuit breaker according to the present inven- =0 tion having a portion of the cover broken away to show internal parts.

Figure 2 is a sectional view taken on the line 11-11 of Figure 1.

Figure 3 is an enlarged sectional view taken 5 on the line III-III of Figure 1.

Figure 4 is a partial sectional view taken on the line IVIV of Figure 3.

Figure 5 is a partial sectional view taken on the line VV of Figure 4.

0 Figure 6 is a detail perspective view of the contact plate.

Figure '7 is a partial front view with the cover removed of a modified form of the invention,

, utilizing the magnetic yoke.

Figure 8 is a sectional view taken on the line VIIIVIII of Figure '7.

Figure 9 is a sectional view taken on the line IX-JX of Figure '7.

0 The circuit breaker as herein illustrated and described embodies the main structural and operating features of that described in appllcants copending application, Serial No. 36,247, filed August 15, 1935, entitled Circuit breakers, and

5 the present invention constitutes an improvement or further development of the invention disclosed therein.

As shown, the circuit breaker comprises. an enclosure having a cup-shaped insulating base I having a cover 2 sealably secured thereto as by 5 rivets 3. A partial wall 4 is disposed substantially centrally of the interior of the base 4 and is provided with a central cutout portion receiving a contact plate 5. A fibre liner 6 is disposed in this cutout portion beneath the contact plate 10 and the plate and liner are rigidly held in position by stud l threaded into the plate. The plate is provided adjacent its corners with pressed up portions to which are secured the stationary contacts 8 and between the adjacent contact supporting portions is provided with openings 9 for the release of are gases. Coopcrating with the stationary contact surfaces 8 are four individual floating contact bars H carrying contact surfaces 12 at one end adapted to engage and disengage their cooperating stationary contacts. The bars II are latched at their opposite ends by bimetallic members l3 adjustably supported on connectors l4 leading to the exterior of the circuit breaker enclosure. Flexible leads [5 interconnect the free ends of the bimetallic members l3 and an intermediate point on the cooperating bars I I. Compression springs l6 bias the bars ll against their respective stationary contacts 8 and bimetallic latches 3@ Hi. The top edges of the bars i i are provided with notches ll received within partial slots iii in one of the legs of rectilinear movable members I9 generally U-shaped in cross section. The other legs of the members l9 are considerably shorter than those in which the slots l8 are located and are adapted to engage within notches 2| in the top edges of the bars ll to restrict the rotary movement of the bars to be hereinafter described. The members iii are guided for rectilinear movement at right angles to the bottom of the base by suitable guides therein.

Operating handles 22 are pivotally mounted on shafts 23 and have interior cam surfaces 24 including flat portions 25 and resetting tips 26. It can readily be seen that rotation of the handle 22 will cause the cam surface 24 to slide over the top face of the member H to cause a rectilinear movement thereof. A spring 21 is provided on the handle to provide a definite position when the contacts are engaged as at the right in Figure 2. The operating features of the handle are more fully described in applicants copending application, Serial No. 72,035, filed April 1, 1936.

The are chambers formed between the general- 1y central wall 4 and the side walls of the base are provided with fibre liners 28 generally U- shaped in cross section, and extending to the liner 5 in the middle and beyond the liner to the top of the walls 4 at one side. At the opposite side the liners 28 extend considerably beyond the contact plate 5.

To enclose these chambers from the operating mechanism barrier walls 29 are provided.

These walls are removably received in notches in the side and bottom walls of the base and the central wall 6 and are themselves centrally notched to clear the wall l. These barrier walls 29 are provided adjacent their bottom portions with restricted slots 3| closely receiving and guiding the bars i i. Within the arcing chambers formed by the liners 28 and the barrier walls 29 are disposed partial transverse plates 32 supported by tongue and slot connections with the side walls of the liner 28. The plates 32 are provided with slots 33 through which the movable contacts i2 pass in their movement to engage and disengage the stationary contacts 8. a

The cover 2 is provided with enlarged openings 34 receiving but having their edges spaced from the operating handles 22 and beneath the cover 2, which may be of metal if desired, is disposed a thin insulating sheet 35 of fibre or other material serving to separate the cover from direct contact with the base. The insulating sheet 35 is pro vided with restricted openings smaller than necessary to receive the handles 22 and the edges of these openings are resiliently pressed inwardly as at 36 to closely embrace the handles 22 to minimize the blowing out of arc gases from the handle openings.

The circuit breaker unit shown at the right in Figure 2 is in the contact engaged position. To manually move the contacts to "off position the handle is rotated to engage the fiat surface 25 with the top of the member l9 whereupon the parts assume the position shown in reverse at the leftin Figure 2 with the movable contact i2 separated ,from the stationary contact 8. To move the contacts again into engaged position the handle is moved to its original position whereupon contact i2 moves into engaged position.

Upon the occurrence of an overload current through any breaker unit the corresponding bimetal will become heated and will bend toward the end of the base, thus unlatching the corresponding end of the bar I! which then rotates under the bias of its spring i6 about the pivot point formed by the engagement of the notch i1 inthe top of the slot l8 in the member i9. This rotary movement continues until the notch it engages the shorter leg of the member I9. In this tripped position the member l9 will move upwardly and will rotate the handle 22 beyond the on position against the bias of the light spring 21 into a position indicating the tripped position of the corresponding breaker unit. To reset the breaker mechanism, the handle is rotated beyond the off position, whereupon the resetting tip 26 on the handle pushes the member l9 beyond the position shown at the left in Figure 2 so that by the engagement of the contact carrying end of the bar H with the bottom of the arc chamben the latching end will be moved beyond the bimetal l3, whereupon by release of the handle it will again move into latched position. This operation is more fully described and claimed in the aforementioned copending applications.

It is seen that the opposite circuit breaker elements are enclosed within common are chambers which are substantially blocked oil from the operating mechanism. Upon the occurrence of an arc between a pair of cooperating contacts the gases generated will move into the relatively large open space above the contact plate 5 through the opening 5 and through the space at the sides of the contact plate. The slots 33 in the plate 32 appear to have a beneficial effect in quenching an are drawn between the cooperating contacts as the movable contact 12 passes therethrough. The midportion of the plate serves as a deflector for the products of any are which may be drawn. It is noted that the conducting parts within the arc chamber can contact only the fibre or other special are resisting material which greatly improves the dielectric characteristics of the circuit breaker. The insulating sheet 35 prevents leakage from the base i or the handle 22 to the metal cover 2 and further minimizes the blowing out of arc gases at the handle opening as it can be seen that any gases reaching the handles will serve to press the fiaps 8'6 against the cooperating handle surfaces to more effectively seal the opening.

Figures '7 to 10, inclusive, show a modified form of arc chamber for the same circuit breaker operating mechanism as that shown in the preferred form of the invention. Here the contact plate 45 is similarly supported on a central wall 44 by a stud ll threaded into the plate. The barrier walls 29 may be omitted if desired and the bar il guided between projections on the side walls of the base and the central wall as shown. Against the walls 56 and the side walls of the base are disposed magnetic yokes 48 having elongated side walls extended along the walls 44 and the side walls of the base and having a central connecting portion 39 received within a'corresponding recess in thebottom of the base. A fibre plate 5! may be provided over the connecting portion 39 to insulate it from the contact carrying ends of the bars II more particularly in their resetting position. A fibre piece 5| of inverted U-shape has its legs engaging the front edges of the yokes 68 to hold them in place and the fibre piece 5! may be held in place by nut 52 on the stud All. This fibre piece is provided with openings 53 above the openings in the contact plate to provide passage of arc gases. The fibre piece 5! may also be provided with notches 54 to provide clearance for the upper edge of the bars II. In this form oi applicant's invention it is seen that the opposite circuit breaker units have common magnetic side walls which may be provided with the joining portion adjacent a mid point. The magnetic effect produced by the above described magnetic yoke aids in blowing out any arcs formed between the cooperating contacts as they are separated.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims:

What is claimed is:

1. In an electric circuit breaker, electrically connected stationary contacts, movable contact members extending in opposite directions from said stationary contacts, said members carrying contact surfaces adjacent one end cooperating with said stationary contacts, U-shaped fibre liner means alongside the contact surfaces on said members, and fibre plates at opposite endsdf said stationary contacts having slots therein receiving and guiding said members, said liner means and opposite plates defining an arcing chamber common to both of said stationary contacts andthe movable contact surfaces cooperating therewith, whereby arc gases incident to an arc drawn between either cooperating pair of contacts and contact surfaces are generated within the common chamber.

2. In an electric circuit breaker, a stationary contact plate having spaced contact surfaces mounted thereon, oppositely extending movable switching members having contact surfaces at their inner ends cooperating with said stationary contact surfaces, individual manual and automatic actuating means for-said members, and side and end walls forming an arc chamber about and common to said contact surfaces, said endwalls having partial slots therein receiving and guiding said members.

3. In an electric circuit breaker, a stationary contact plate having spaced contact surfaces mounted thereon, an opening in said plate between said surfaces providing passage for are gases, oppositely extending movable switching members having contact surfaces at their inner ends cooperating with said stationary contact surfaces, individual manual and automatic actuating means for said members, and side and end walls forming an arc chamber about and common to said contact surfaces, said end walls having partial slots therein receiving and guiding said members.-

4. In an electric circuit breaker, a generally cup-shaped base, a stationary contact surface spaced from andfacing the bottom of said base, a movable contact member carrying a contact surface disposed between said stationary contact surface and the bottom of the base, manual and automatic. operating means for moving said member, a barrier wall disposed between said operating means and contact surface, said wall extending adjacent to the top of the base and having a restricted slot adjacent its bottom portion receiving said movable member, and a flat cover for said base engaging the top of said wall and cooperating therewith to substantially isolate the contact surfaces from the operating means.

5. In an electric circuit breaker,.a generally cup-shaped base, a pair of electrically connected stationary contact surfaces disposed between the ends of said base and spaced from and facing the bottom of the base, movable conducting members disposed between the stationary contact surfaces and the opposite ends of the base, said members carrying contact surfaces at their inner ends cooperating with the stationary contact surfaces, individual manual and automatic operating means for moving said members, spaced barrier walls disposed between the stationary contact surfaces and the operating means, each of said walls having a restricted slot receiving and guiding the cooperating movable member, and a flat cover for said base engaging the tops of said walls and cooperating therewith to substantially isolate the contact surfaces from the operating means.

6. In an electric circuit breaker, a generally cup-shaped base, a stationary contact plate spaced from the bottom of the base and having contact surfaces thereon facing the bottom of the base and spaced toward the ends of the base, anopening through said plate between said surfaces providing passage for are gases, individual movable contact surfaces cooperating with said stationary surfaces and carried by elongated conducting members oppositely extending toward the ends of the base, individual manual and automatic operating means for moving said members, insulating walls alongside and below said contact surfaces, and spaced barrier walls between said operating means and contact surfaces and extending adjacent to the top of the base, said barrier walls having restricted slots adjacent their bottom portions receiving said members.

7. In an electric circuit breaker, a conducting element carrying a contact surface thereon, a movable switching element having a contact surface cooperating with said first mentioned contact surface, and an opening through said conducting element adjacent to said first mentioned contact surface providing passage for are gases generated by an arc drawn between said contact surfaces.

8. In an electriccircuit breaker, a base, a stationary contact plate mounted on said base and having spaced contact surfaces thereon, an opening through said plate between said surfaces providing passage for are gases, movable members carrying contact surfaces cooperating with said first mentioned surfaces, and individual manual and automatic means for moving said members.

9. In an electric circuit breaker, a base, a conducting plate spaced from the main body of the base and carrying spaced contact surfaces facing toward the main body of the base, an opening through said plate between said surfaces providing passage for are gases, movable contact surfaces disposed between the main body of the base and said first mentioned surfaces, and man ual and automatic means for moving said movable contact surfaces.

10. In an electric circuit breaker, a generally cup-shaped base, a stationary contact surface spaced from and facing the bottom of said base, a movable contact member carrying a contact surface disposed between said stationary contact surface and the bottom of the base, manual and automatic operating means for moving said member, insulating walls on opposite sides of said movable contact surface, an insulating plate between said walls in the path of said movable contact surface, and a slot in said plate through which said. movable surface passes in engaging and disengaging said stationary surface.

11. In an electric circuit breaker, a generally cup-shaped base, a stationary contact surface spaced from and facing the bottom of said base, a movable contact member carrying a contact surface disposed between said stationary contact surface and the bottom of the base, manual and automatic operating means for moving said member, insulating walls on opposite sides of said movable contact surface, an insulating plate between said walls in the path of said movable contact surface, a slot in said plate through which said movable surface passes in engaging and disengaging said stationary surface, and a barrier wall disposed between said operating means and contact surfaces and having a restricted slot adjacent its bottom portion receiving and guiding said member.

12. In an electric circuit breaker, a generally cup-shaped base, a pair of electrically connected stationary contact surfaces disposed between the ends of said base and spaced from and facing 'the bottom of the base, movable conducting members disposed between the stationary contact surfaces and the opposite ends of the base,

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said members carrying contact surfaces at their inner ends cooperating with the stationary contact surfaces, individual manual and automatic operating means for moving said members, a transverse insulating plate disposed across the path of movement of said movable contact surfaces, and slots in said plate through which said movable surfaces pass in engaging and disengaging said stationary surfaces.

13. In an electric circuit breaker, a generally cup-shaped base, a stationary contact plate spaced from the bottom of the base and having contact surfaces thereon facing the bottom of the base and spaced toward the ends of the base, an opening through said plate between said surfaces providing passage for are gases, individual movable contact surfaces cooperating with said stationary surfaces and carried by elongated conducting members oppositely extending toward the ends of the base, individual manual and automatic operating means for moving said members, insulating walls alongside of and below said contact surfaces, a transverse insulating plate disposed across the path of movement of said movable contact surfaces, and slots in said plate through which said movable surfaces pass in engaging and disengaging said stationary surfaces.

14. In an automatic electric circuit breaker, electrically connected stationary contact. surfaces, movable contact surfaces cooperating therewith, individual manual and automatic means for moving said movable'contact surfaces, and spaced magnetic plates common to both sets of contact surfaces anddisposed on opposite sides of the path of movement of both said movable contact surfaces.

15. In an automatic electric circuit breaker, electrically connected stationary contacts, movable members extending in opposite directions and carrying contact surfaces at their adjacent ends cooperating with said stationary contacts, individual manual and automatic means for moving said members, and spaced magnetic plates common to both sets of cooperating contacts and contact surfaces and disposed on opposite sides of and with their planes substantially parallel to the path of movement of said movable contact surfaces.

16. In an automatic electric circuit breaker, electrically connected stationary contacts, movable members extending in opposite directions and carrying contact surfaces at their adjacent ends cooperating with said stationary contacts, individual manual and automatic means for moving said members, spaced magnetic plates common to both sets of cooperating contacts and contact surfaces and disposed on opposite sides of and with their planes substantially parallel to the path of movement of said movable contact surfaces, and a transverse magnetic portion joining said plates beyond the extreme position of said movable surfaces.

17. In an automatic electric circuit breaker, electrically connected stationary contacts, movable members extending in opposite directions and carrying contact surfaces at their adjacent ends cooperating with said stationary contacts, individual manual and automatic means for moving said members, spaced magnetic plates common to both sets of cooperating contacts and contact surfaces and disposed on opposite sides of and with their planes substantially parallel to the path of movement of said movable contact surfaces, a transverse magnetic portion joining said plates beyond the extreme position of said matic means for moving said members, elongated magnetic plates common to both sets of cooperating contacts and contact surfaces and disposed on opposite sides of the path of movement of said adjacent ends of said members and a magnetic portion joining substantially the middle 3 portions of the edges of said magnetic plates re- I mote from said contact plate.

19. In an automatic electric circuitbreaker a base, separable contacts and automatic and manual means for actuating said contacts mounted on said base, a cover for said base, an operating handle projecting through an enlarged opening in said cover which provides substantial clearance between the cover and the handle, and a stationary thin insulating sheet separating said cover from the base and having a smaller opening relatively closely receiving said handle to substantially prevent the blowing out of arc gases through the cover opening.

20. In an automatic electric circuit breaker, a substantially cup-shaped base, separable contacts and automatic and manual means for actuating said contacts mounted on said base, a cover for said base, an operating handle projecting through an enlarged opening in said cover, and a stationary thin sheet of insulation lining said cover and having a smaller opening closely embracing said handle, said insulating sheet thus closing the enlarged cover opening about the handle and inhibiting the blowing out of arc gases generated within the circuit breaker interior.

21. In an automatic electric circuit breaker, a substantially cup-shaped base, separable contacts and automatic and manual means for actuating said contacts mounted on said base, a metallic cover for said base, an operating handle projecting through an enlarged opening in said cover, and a stationary thin sheet of insulation lining said cover and having a smaller opening closely embracing said handle, the opening in said sheet being smaller than said handle and. the edges thereof being bent against and interiorly of said handles to prevent blowing out of arc gases.

' 22. In an automatic electric circuit breaker, a base, electrically connected stationary contacts, aplurality of individual movable contacts, individual manual and automatic operating means for moving said movable contacts, a cover for said base, said means including handle portions extending through said cover, the cover openings being substantially larger than said handle portions to provide clearance thereto, and a stationary thin fibre sheet provided with openings closely embracing said handle portions, said fibre sheet thus closing the cover openings about the handle portions and inhibiting the blowing out of arc gases generated within the circuit breaker interior.

23. In an electric circuit breaker, a generally cup-shaped base, a stationary contact surface disposed within said base, a movable contact member carrying a contact surface adapted to cooperate with said stationary contact surface, manual and automatic operating means for movamass? ing said member to perform the switching operation, a barrier wall disposed between said cooperating contact surfaces and said operating means and having a slot adjacent its bottom portion receiving said member, said wail being slidably interlocked with formations within the base to restrict movement thereof except forwardly at right angles to the back of the base, and cover means sealably attachable to said base and maintaining said plate in position therein.

24. In an electric circuit breaker, a generally cup-shaped base, a stationary contact surface disposed within said base, a movable contact member carrying a contact surface adapted to cooperate with said stationary contact surface, manual and automatic operating means for moving said member to perform the switching operation, a barrier wall disposed between said cooperating contact surfaces and said operating means and having a slot adjacent its bottom portion receiving said member, said wall being slidably interlocked with formations within the base.

to restrict movement thereof except forwardly at right angles to the back of the base, and cover means sealably attachable to said base and maintaining said plate in position therein, said wall extending to said cover to substantially isolate the cooperating contacts and any arcs drawn therebetween from the operating means.

25. In an electric circuit breaker, a generally cup-shaped base, a stationary contact surface disposed within said base, a movable contact member carrying a contact surface adapted to cooperate with said stationary contact surface, manual and automatic operating means for moving said member to perform the switching operation, a barrier wall disposed between said cooperating contact surfaces and said operating means and having a slot adjacent its bottom portion receiving. said member, said wall being slidably interlocked with formations within the base to restrict movement thereof except forwardly at right angles to the back of the base, cover means sealably attachable to said base and maintaining said plate in position therein, said wall extending to said cover to substantially isolate the cooperating contacts and any arcs drawn therebetween from the operating means, and a restricted opening between said cover and base providing for the venting of any gases generated by an are drawn between said cooperating contact surfaces.

26. In an electric circuit breaker, a generally cup-shaped base, electrically connected station- V ary contact surfaces disposed substantially intermediate the ends of the base, aligned movable contact members carrying contact surfaces adapted to cooperate with said stationary contact surfaces, individual manual and automatic operating means for moving said members to perform the switching operations, there being at least one member and operating means disposed between said stationary contact surfaces and each end of the base, a barrier wall between i said stationary contact surfaces and the operat-' cup-shaped base, electrically connected stationary contact surfaces disposed substantially intermediate the ends of the base, aligned movable contact members carrying contact surfaces adapted to cooperate with said stationary contact surfaces, individual manual and automatic operating means for moving said members to perform the switching operations, there being at least one member and operating means disposed between said stationary contact surfaces and each end of the base, a barrier wall between said stationary contact surfaces and the operating means at each end of the base, said barrier walls having slots adjacent their bottom portions receiving said members, a cover for said base, said barrier walls being slidably interlocked with said base to restrict relative movement except at right angles to the back of said base and being maintained in position by said cover, said walls cooperating to form an arcing chamber about said contact surfaces.

28. In an electric circuit breaker, a generally cup-shaped base, electrically connected stationary contact surfaces disposed substantially intermediate the ends of the base, aligned movable contact members carrying contact surfaces adapted to cooperate with'said stationary contact surfaces, individual manual and automatic operating means for moving said members to perform the switching operations, there being at least one member and operating means disposed between said stationary contact surfaces and each end of the base, a barrier wall between said stationary contact surfaces and the operating means at each end of the base, said barrier walls having slots adjacent their bottom portions receiving said members, a cover for said base,

said barrier walls extending substantially to the cover to form an arcing chamber enclosing said contact surfaces and substantially isolated from said operating means, and a restricted opening at the junction of said cover and base for the venting of arc gases generated within said chamber.

29. In an electric circuit breaker, a generally cup-shaped base, stationary and movable contacts and manual and automatic operating means for moving said movable contact to per-- form the switching operation, said contacts and operating means being disposed within said base, and a flat cover plate sealably attached to said base to enclose said means from exterior access except for a manual operator projecting through the cover, and a restricted opening formed at the juncture of said cover plate and base and serving for the venting of arc gases generated within the base.

30. In an electric circuit breaker, a generally cup-shaped base, stationary and movable contacts and manual and automatic operating means for moving said movable contact to perform the switching operation, said contacts and operating means being disposed within said base, insulating formations within said base forming an arc chamber about said contacts and substantialiy shielding said operating means, a cover plate seaiably attached to said base to prevent access to the interior thereof, and a restricted opening formed at the juncture of said cover plate and base and in communication with I said arc chamber to vent to the exterior of the base are gases generated within the chamber.

JOHN G. JACKSON. 

